Patent GB-784142-A (GB)
Title: Mechanism and method for classifying and assorting metal sheets
Inventor: CAMP JAMES BLOISE
IPC: B23Q7/12
Filed: 1954-08-13
Abstract: 784,142. Photo - electric sheet sorting. UNITED STATES STEEL CORPORATION. Aug. 13, 1954, No. 23639/54. Class 40 (3). [Also in Group XXII] In metal sheet sorting apparatus in which continuous strip is fed to a shear and seperate sheets away from it, a magnetic roll deflector is positioned beyond the shear and is actuated by the leading edge of an imperfect sheet for routing it to a " reject " bin. General operation.-As shown (Fig. 1) continuous strip 1 is fed past a pin-hole detector 14 preferably of the photo-electric type, a defective sheet marker 16 and a thickness gauge 15 to a rotary flying shear 2 and the separate sheets are fed to a prime sheet piler or a reject piler 5, according as the magnetic roller deflector 8 is energized or not. A pair of magnetic recording tracks 20, 21 are driven at a speed proportional to the strip speed and are used to actuate the strip marker 16 and the magnetic roll deflector at the correct instant. When the pin-hole detector 14 detects an imperfection in the strip it produces an output pulse which is shaped at 30, amplified at 31 and recorded on the magnetic track 20 by head 22. Spaced from recording head 22 is a reading head 24 controlling the sheet marker so that the mark is made when the imperfection arrives beneath it. Also spaced around the magnetic track 20 are an off-gauge recording head 23 and a reading head 25 at positions corresponding to the gauge 15 and the flying shear 2. Thus any spot recorded on the track reaches reading head 25 at the same time as the corresponding imperfection arrives at the shear. Reading head 25 " cocks " a storage circuit 34 through an amplifier 35 and closure of contacts 36 by the flying shear resets the circuit and sets a second storage circuit 38, thus recording that the sheet just cut has an imperfection. The control is now made dependent on the leading instead of the trailing edge of a sheet by means of a photo-cell 39 and light source 40 which detect the leading edge of the sheet and control a " flip-flop " circuit 41. This flip-flop has two alternative current paths which conduct according as the cell is exposed to light or darkened by a sheet. When storage circuit 38 is set and the leading edge of a sheet interrupts the light to the cell the signal is transferred to a third storage circuit 42. This circuit keys an oscillator 43 as long as cell 39 is darkened although it resets itself. The oscillator output is recorded on the second magnetic track 21 and thus a recorded band is produced proportional to the length of the defective sheet. The spacing between recording head 27 and pick-up 28 is proportional to the spacing of the photocell 39 from the deflector roll 8. The roll is normally energized and guides sheet to the " prime " bin 4. The signal from the oscillator de-energizes it just before the arrival of the defective sheet allowing the sheet to fall beneath a deflector into a reject bin 5. The magnetic roll deflector (Fig. 2) consists of a hollow cylinder 8 of non-magnetic material rotating on bearings 10 on a shaft 9 and driven by means of pulleys 11. Mounted on the axial shaft are electromagnets 13 and when these are energized the metal sheet is held in contact with the roll. Magnetic memory device (Fig. 4) comprises a rotor of machined aluminium carrying on its circumference two recording tracks 20, 21 formed of many turns of recording wire. The rotor is chain driven and spaced around its periphery are recording and reading heads such as 22.